Carburetor



May 21, l929- I E. scHlMANEK I 1,714,441

` CARBURETOR Filed Feb. 2s, 1926 WIr/111111111 57m? clima ne/ Patented May 21,19-29l l UNITED STATES EMIL scHmANEx, 0E BUDAPEST, HUNGARY, AsSIGNon. 'ro THE FIRM HERMES MAGYAE ALTALNos vL'rzLE'r RSzvENxTARsAsAG, or BUDAEEST, HUN- GABY.

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Application led February 26, 1926, Serial No. 90,898, and in Hun-gary June 27, 1925.

This invention relates to a carburetor for automatically regulating the ratio of air and fuel according to the different speeds of the internal combustion engine with which itis employed. In this carburetor a regulating piston is provided to alter the section of passage of the air flowing through the carburetor and, simultaneously, the section of pas- -sa of the fuel admission, in such a manner that the ratio of mixture is either kept constant by the changes of position of said piston or is altered according to a predetermined scheme. It will be understood that for each speed of the engine there is a corresponding position of said piston, determining the ratio of mixture of air and fuel.

The object of this invention is to allow the ratio of air and fuel in the mixture to4 be altered either automatically or at will .by the operator, even if the speed of the engine is not changed.

According to the invention, the regulating piston is adapted to control the area of the air passage into .which the fuel c hannel d1scharges, on the one hand by lts vertlcal movement caused by changes in the speed of the engine and on the other hand b the rotation of said piston which may be e ected f either by the operator or by changes in atmospheric pressure.

The annexed drawing shows two embodiments of the invention.-

Figure 1 is a sectional view of a carburetor in which the adjustment of the piston is effected manually; A y

Fig. 2 is a vertical section of the piston on line 2--2 of Fig. 1;

Fig. 3 is a sectional view of another form, in which the regulation of the air and fuel takes place automatically according to the changes in atmospheric pressure;

Fig. 4 shows a detail of Fig- 3 on a larger scale. With reference to Fig. 1, 1 is the casing of the carburetor, 2 is the air inlet, 3 is a float chamber containing liquid fuel 4, and 5 is a iloat located therein. 6 is a lever pivoted at 7, resting on the top of float 5, and 8 is a valve controlling the admission of liquid fuel from the fuel conduit 9 to the oat chamber 3. 10 is the stem of valve 8, resting upon lever 6. 11 is a cylindrical upper part of the casing 1 of the carburetor,-

andA 12 is a piston movable therein, said piston serving as a means for automatically regulating the area of the passages for air and fuel admission. 14 is a mixingchamber, and 13 1s an opening connecting the cylindrical part 11 of the casing 1 with said mixing chamber 14. 15 is a cylindrical projection or skirt on the piston 12 co-operating with said cylindrical part 11 to control the area of opening 13. This latter is shaped to have an oblique edge 16, and projection 15 has an oblique edge 17 parallel with edge 16.

Channel 19 of the hollow stem 18 of piston 12 is connected with horizontal channels 2() (Fig. 2) discharging within the area of opening 13. Channels 21 are provided to connect 'the discharge ends of the channels 20 with the upper side of piston 12. A sleeve 22 provided with a circular base plate 23 is secured to the lower end ofstem 18, and a perforated disc 24 is secured between stem 18 and sleeve 22. Plate 23 fits loosely into the lower cylindrical part 48 of the vcarburetor casing. penings 25 i-n sleeve 22 admit the liquid fuel through the perforation of disc 24 into channel 19.` A tapered needle 26 secured to the bottom of the vcarburetor casing projects through the perforation of disc 24 into channel 19.

Journalled in stuiiing box 27 on" the top of the carburetor casing is a shaft 28 provided at its lower end with a disc 29, and piston 12 1s provided with an upwardly projectingpin 30 engaging an opening 31 in disc 29. 32 is a controlling lever 'secured tov The fuel is admitted from the fuel conduit 9 through valve 8 into the float chamber 3 until float 5 closes valve 8 by means of lever 6. The air is sucked in` through opening 2 into the carburetor casing and passes through opening 13 into the mixing chamber 14. At the same time the fuel' asses through openings 25 and the perforation of disc 24 into the channel 19 of stem 18 of piston 12 and, owin to the suction, rises in channel 19 in or er to discharge through channels 20 and opening 13 into the'mixing chamber. The mixture leaves the carburetor through the induction pipe or conduit 49.

As the chamber 33 above piston 12 communisure acting on the lower face of piston 1 2 will be that of the atmosphere. The position ofe uilibrium of piston 12 will be de-` termined y the speed of the engine.

It will be understood that the pressures acting at both sides of the piston should be static ones. The connection of the discharge end of the fuel channels 2() by means of channels 21 with the closed chamber 33 above piston 12, in which the air is at rest, causes the dynamic ressure occurring at the discharge end o the fuel channel to act as fa static pressure upon the piston. In order that the pressure below the piston may be substantially. a static one, the area of the piston must be a multiple of the free area of theair admission opening 13, so that the velocity of the air under the piston will practically not alter the pressure. The pressure acting on the upper side of the piston will be less than the pressure acting on the lower side so that the piston would be lifted to its -uppermost position if its weight did not counteract lthe lifting action. As this weight is constant, the piston will reach a state of equilibrium if the difference between the pressures acting on `the lower and upper sides of said piston is constant. As, however, owing to the great areaof the piston, the pressure below the piston is independent of the quantity of the air flowing through the carburetor, the pressure acting upon the upper side of the piston must be regulated automatically to a constant value independently of the quantity of air flowing through the carburetor. Hence the velocity Vof the air at the spot where the mixing of the air and fuel takes place will be regulated to a value which is constant independently of the quantity of air sucked in by the engine; that is to say, the piston will assume a position in which the area of opening 13 is altered in such a manner that thevelocity of the air in said opening will be constant at any speed of the engine. With alterations of the position of the piston 12, however, the position of disc 24 with respect to needle 26 and, correspondingly, the section of passage of the perforation of said disc left free by needle 26 are altered, so that the ratio of fuel and air admitted through d isc 24 and opening 13 will be altered in conformity with the shape of needle 26, either yaccording to a predetermined scheme or kept constant throughout the range of s eed of the engine. Generall it will be en eavoured to keep the ratio o air and fuell constant throu hout the ran e of I'speed of the engine.

yhis ratio' W' be termed the fundamental ratio.

It is, however, desirable to alter this funi damental ratio according to the nature of the fuel used, or according to the specific wei ht of the air, which varies within wide limits if the motor is used on air craft. For

this purpose means are provided according to my invention allowing alteration of the ratio of thesections of passage ofthe air and fuel in the carburetor in any position of the automatic piston 12 without altering the position of this latter.

According to Fig. 1, this is keii'ected by turning handle 32, so that shaft 28 turns piston 12 by the intermediary of disc 29 and pin 30, and thereby produces a decrease 7 or increase of the distance of edge 17 of skirt 15 from edge 16 of, opening 13 without altering the level of piston 12. This adjustment by twisting piston 12 does not a-ffeet the automatic adjustment of said piston in the vertical direction. Plate 23 serves to chokethe vibrations of piston 12.

.According to Figs. 3 and 4, the adjustment of the piston is effected automatically by changes in atmospheric pressure.

For this purpose the adjusting disc 29 that engages pin 30 of piston 12 is journalled on a stud 41, secured to a diaphragm 42 whichhermetically closes a chamber 43. The chamber 43 is filled with a gas under a cer- .tain pressureyfor example the normal atmospheric pressure at sea level. If the atmospheric pressure decreases, the gas filling chamber 43 expands and lowers stud 4I' with disc 29. An oblique slot 44 (Fig. 4) formed in a projection 45 on disc 29 engages pin 46 secured in the carburetor casing, so that the vertical displacement of disc 29 causes, by the cooperation of slot 44 and pin 46, the` rotation of said disc and, by the mediation 1 of in 30, the rotation of piston 12.

claim as my invention 1. A carburetor, comprising a casing partitioned internally to form an air inlet chamber and a mixing chamber, such parti- 1 tion having an opening providing communication between said air and mixing chambers; a fuel chamber in said casing; a fuel conduit leading from the fuel chamber to the mixing chamber to discharge the fuel 1 thereinto; -a piston movable vertlcally with-I in the air chamber to control the effective area of said opening; a depending skirt on the 1piston; a suction chamber in said casin at t e opposite side of the piston from sai air chamber and communicating with the same, said suction 'chamber transmitting the engine suction to said piston to effect its vertical movements; and means for rotating the piston to cause its skirt to vary the said 1 effective area of said opening independently of the vertical position of said piston.

2. A carburetor, comprising a casin a cylindrical partition in the casing to 5mn an air inlet chamber and a mixing chamber, 1 such partition having an opening providing communication between said air and mixin chambers; a fuel chamber in the bottom o the uneasing; a piston movable verticallyf.- wthm said partition to control the effe l area of saidV opening and having a hollow stem submerged at its inlet end in the fuel in the fuel chamber and discharging the fuel at its outlet end through said opening into the mixing chamber; a depending skirt on the piston; a suction chamber in the easing above the piston for transmitting the engine suction to said piston to-efect its vertical movements, said suction chambercommunieating with the air chamber; and means for rotating the piston to cause its skirt to vary the said effective area of said opening independently of the vertical position of said piston.

3. A carburetor, comprising a easing; a cylindrical partition in the casing to form an air inlet chamber and a mixing chamber, such partition having an opening providing communication between said air and mixing chambers; a fuel chamber in' the bottom of the casing; a piston movable vertically Within said partition to control the effective area of said opening and having a hollow stem which is submerged at its lower or inlet end in the fuel in the fuel chamber, the upper end of the bore yof said stem having one or more outlet channels leading from it to discharge the fuel through said opening into the mixing chamber; a depending skirt on the piston; a suction chamberv in the casing above said piston for transmitting the engine suction to the latter to effect its vertical movements, said -suction chamber communicating with said outlet channels by means of separate' channels formed through the piston; and4 means for rotating said piston to cause its skirt to vary the said effective area of said opening independently of the vertical position -of the piston. l

4. A carburetor, comprising a casing provided with a mixing chamber having a` single opening for admitting both air and fuel thereinto for admixture, means for supplying air and fuel separately to said opening, a suetion-operatnd piston movable vertically in the casing to vary the effectivearea of said opening and thereby control both the air supply and the fuel supply to said mixing chamber, a depending skirt on the piston, and means for rotating said piston to cause its skirt to vary the effective area of the opening and thereby control the air and fuel supply independently of the vertical position of the piston, l

5. A carburetor, comprisingr a casing provided with a mixing chamber having a single opening for admitting both air and fuel ther-cinto for admixture, means for supplying ail' and fuel separately to said opening, a suction-operated piston movable vertically 1n the easlng to vary the effectlve area 

